Administration: Individual. The DAB-4 is a revision of one of the most popular individual achievement tests available. Its 8 subtests identify studentsâ strengths and weaknesses across important areas of school achievement. A supplemental manual shows how to probe student responses to obtain information about studentsâ thinking processes and problem-solving strategies.
In 1992, the first evidence of a planetary system other than our own was discovered, orbiting the pulsar PSR B1257+12. Three years later, 51 Pegasi b, the first extrasolar planet around a Sunlike star, was discovered.
Pluto was officially discovered in 1930 by Clyde Tombaugh, and was initially thought to have a mass equivalent to that of Earth. It was, therefore, reasonable to declare Pluto the solar system's ninth planet. Over the years, though, Pluto's mass was found to be smaller and smaller.